/* 进入前 */
.react-enter{
  left:-400px;
}
  
/* 进入中 */
.react-enter-active{
  left:0;
  transition: all .6s;
  position: relative;
}
/* 离开前 */
.react-exit{
  left: 0;
}
/* 离开中 */
.react-exit-active{
  left:-400px;
  transition: all .6s;
  position: relative;
}